An advisory is in effect during times of high for the North Shore of Long Island until 11 p.m.
The warning "means that flooding is occurring or imminent," the National Weather Service said in a statement.
"A coastal flood advisory indicates that onshore winds and tides will combine to generate flooding of low areas along the shore," the statement said.
The flooding is expected during high tide, courtesy of strong northeast winds combined with high astronomical tides "associated with an upcoming new moon," forecasters said.
A high surf advisory remains in effect until 6 a.m. Tuesday.
Pounding surf is expected to produce dangerous rip currents and cause beach erosion at Atlantic beaches into the night, the weather service said.